Gotcha!!

I was scammed at work today. And I am SO frustrated about it. Because I should have known better and I should have caught it. Argh!
The scammer is a customer that I know (not by name but by sight) and she is a big clearance customer. She buys almost only clearance items and returns about 1/3 of it. But she is generally pretty organized and always has her receipts. She seperates her returns and things always match up. Usually her reason for return is wrong size. She is very pleasant but doesn't seem to speak English very well (or pretends not to at least) so we don't speak much. Bottom line, I had no reason to think of her as a "problem customer".
Today she came up with two bags and two seperate returns (of 3 items each). 4 men's shirts and 2 women's. She had her receipts and all tags were attached. I scanned each item, found it on the receipt (a pretty recent receipt), and returned it. Most were $10.00 items, one was a $15.00 item. I took the pile and put it aside, gave her mostly store credit back (because that is how she paid for it, with the balance on her Kohl's charge. And wished her a good day. Then I turned to scan the items and make sure they were ticketed with the correct clearance sticker (red or yellow). I pick up the first shirt and hold it up and see that it looks................used. A little dirty perhaps and felt like is had been washed..... So I enter the number into the computer and see that the tag brand does NOT match the shirt brand. I then find a UPC number in the shirt and check it to the one on the tag. As I feared, no match. ARGH!!!! This wasn't a huge deal though because the price difference was only $3.00. But still!! I show my co-worked and then give the customer the benefit of the doubt. She is a usual customer and her returns are always in order and so maybe we were scammed by another customer, no one caught it, and the shirt was put out on the floor. And this unsuspecting customer picked it up and bought it.......
And then I checked the second shirt. Same thing!! But this was a $1.00 item that she got $10.00 back for!!! This was the same vendor but the tags and numbers weren't the same. These were even easy to check because the UPC was in the shirt!!! I don't think this one was worn but it was kind of hard to tell.....
The other items were fine except for a woman's blazer that may or may not have been the correct item.......
I was scammed!!!!!! I guess it happens to the best of us (hehe) and I can't let my guard down. I just look forward to the next time she comes in............. I hope she tries it again. And she tries it with me. Not that I can say anything about the previous time but I can catch her trying it again. And let LP (Loss Prevention) know to keep an eye on her.
Because I am sure Clearance Lady will be back.................................
And I will be waiting..............................